Rope ladders, which are especially useful as pilot's ladders by which a local pilot boards or leaves a ship, used to be made with wooden or metal steps until my earlier inventions, shown in U.S. Pat. Nos. 4,177,878 and 4,241,809, incorporated a molded elastomer step of a hard rubber-like material. The present invention relates to improvements in that type of ladder.
Those patents disclose and claim a rope ladder of the type in which there are two ropes on each side of each molded step, and a wedging structure is used to make the attachment between each step and the ropes secure. However, the molded steps sometimes proved weaker than was desired for long life. In the present invention, I incorporate a strong metal frame having a special shape around which is molded the body of the step.
The breakage and non-uniformity of wooden steps had long been a problem, and the use of molded elastomer in my earlier patents greatly reduced breakage and gave improved quality control. Also, the elastomer had more resilience and so better received strong impacts. When improved according to the present invention, the step will not flex or bend under average work load, but on the other hand the molded portion especially can yield to very strong loads or impacts without actually breaking.
However, under some conditions any steps can break or be unduly weakened. Heretofore, replacement of even one step meant taking the whole ladder apart and putting it back together. Therefore, an object of the present invention is to provide a novel replacement step that can be installed without having to take the whole ladder apart.
Sometimes the collars used as part of the wedging structure are broken or damaged severely, and the present invention solves that replacement problem too.